Technical Field
This invention relates generally to energy management, and more particularly to methods and systems of charging to improve battery cycle life.
Background Art
Portable electronic devices, such as cellular telephones, laptop computers, tablet computers, pagers, and two-way radios for example, derive their portability from batteries having rechargeable cells. These batteries allow these devices to slip the surly bonds of power supplies tethered to walls and to travel wirelessly with users wherever they may go. A typical battery disposed within one of these devices may be charged and discharged hundreds of times over its lifetime. This is particularly true due to the daily reliance people increasingly place upon their personal devices.
When a rechargeable battery is new, the cells within that battery can typically be charged to their maximum rated capacity. Said differently, one hundred percent of the cell capacity is available to store and deliver energy when the battery is new. As the battery is charged and discharged over the course of its life, however, its energy storage capacity, which measures the battery's capability to power a device, decreases due to chemical changes within the cells. For example, after roughly 400 charge/discharge cycles, the cells within a battery may only be chargeable to eighty-five or less percent of their original maximum capacity. As a result, a user may notice that the portable electronic device that receives its power from the battery does not provide as much run time for active operations or idle time for standby operations between charging cycles as the device initially did.
It would be advantageous to be able to reduce changes in capacity over time.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.